[captainclock1988]

I was given Newcomb's bigger version of this Amplifier which was a Newcomb "Pathfinder" Model E-75 Amplifier that was good for 75 Watts.
The tube line-up of that amplifier was 2 7027-A (KT-88), a 6V6, a 6C4, and 2 12AX7As (All RCA Branded Tubes), and according to the service manual for the Newcomb "Pathfinder" Model E-75 Amplifier, the 6V6 tube in this circuit (and yours as well) was used as a regulator tube (as opposed to using an old school 01A Gas Regulator Tube), so yes in your amplifier the 6V6 tube is a regulator tube. 

Hope this helps.